Single shot transient suppressor (SSTS) for high current high slew rate microprocessor

Abstract

Future generation microprocessors are predicted to exhibit heavier loads and faster transients. Conventional voltage regulator modules (VRM) need a large amount of output filter capacitors to meet future requirements and a huge number of decoupling capacitors, mainly due to the presence of parasitic inductance between the VRM and the microprocessor. In this paper, a new active damp concept is presented. By charging some auxiliary capacitors at higher voltage, it is possible to store the amount of charge required by the processor during the step up transient; this extra charge can be locally delivered to the processor in a single shot manner, bypassing the slower VRM. In the same way, this circuit can sink the excess of charge that has to be removed during the step down transient. By using this transient suppressor circuit, a conventional VRM can still provide adequate steady state regulation, while the size of decoupling and filter capacitors can be significantly reduced. Experimental results prove the validity of the concept.